Estimation of inter-laboratory reference change values from external quality assessment data.

Area of Science:

• Laboratory Medicine
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Patient care continuity is challenged by fragmented healthcare, impacting long-term condition monitoring.
• Inter-laboratory measurement uncertainty complicates data mining from diverse laboratory results.
• Standardizing laboratory data interpretation requires understanding inter-laboratory variability.

Purpose of the Study:

• To estimate inter-laboratory reference change values (IL-RCVs) for key analytes.
• To demonstrate a proof-of-concept using publicly available external quality assessment (EQA) and biological variation data.
• To assess the feasibility of quantifying inter-laboratory variability for routine laboratory tests.

Main Methods:

• Analyzed EQA data from the Reference Institute for Bioanalytics (RfB) for serum creatinine, calcium, aldosterone, PSA, and whole blood HbA1c.
• Calculated median coefficients of variation (CVs) from EQA campaigns.
• Estimated positive and negative IL-RCVs using log transformation and intra-individual biological variation data from the EFLM database.

Main Results:

• Successfully estimated IL-RCVs for all examined analytes.
• Positive IL-RCVs ranged from 13.3% to 203%.
• Negative IL-RCVs ranged from -11.8% to -67.0% (e.g., serum calcium vs. serum aldosterone).

Conclusions:

• Freely available EQA and biological variation data can effectively estimate inter-laboratory RCVs.
• Estimated IL-RCVs highlight significant analyte-specific differences.
• These findings aid in defining the interoperability limits within laboratory medicine.